Adhesive composition

ABSTRACT

An adhesive composition for floor coverings, particularly, though not exclusively for reinforced textile stair carpets comprises one part of contact adhesive components which are sticky at room temperature, and which bring about an adhering effect, and one part of synthetic thermoplastic components which are nonsticky at room temperature, but which, however, on heating to a temperature above 60* C. suffer temporary partial loss of their cohesion and become a strong sealing adhesive, which is adapted to form a permanent bond with the base to be bonded.

United States Patent Inventor Guenter Horst Tesch Fribourg, SwitzerlandApp]. No. 705,640 Filed Feb. 15, 1968 Patented Nov. 9, 1971 AssigneeBreveteam S. A.

Fribourg, Switzerland Priority Feb. 22, 1967 Switzerland ADHESIVECOMPOSITION 1 Claim, No Drawings U.S.C| 117/122 H, 161/67, 161/406,260/873 Int. Cl C09j 7/04, D06n 3/04 Field of Search 260/873;

Primary ExaminerWilliam D. Martin Assisran! Examiner-Bernard D. PianaltoAnorney-Ernest G. Montague ABSTRACT: An adhesive composition for floorcoverings, particularly, though not exclusively for reinforced textilestair carpets comprises one part of contact adhesive components whichare sticky at room temperature, and which bring about an adheringeffect, and one part of synthetic thermoplastic components which arenonsticky at room temperature, but which, however, on heating to atemperature above 60 C. suffer temporary partial loss of their cohesionand become a strong sealing adhesive, which is adapted to form apermanent bond with the base to be bonded.

BACKGROUND OF THE INVENTION The present invention concerns an adhesivecomposition for floor coverings, particularly, though not exclusivelyfor reinforced textile stair carpets.

Floor coverings are known which are held in place by special adhesivescompatible with the covering material. Thus, for example, imperviousfloor coverings have been used with adhesives which after applicationhave been allowed to partially set in air before the final laying of thecovering, also pervious coverings have been used with aqueousdispersions of synthetic resin adhesives or solvent adhesives.

Recently textile floor coverings have had a back coating of contactadhesive deposited either from a solution or from a dispersion, so as topermit detachable sticking with the floor to be covered. This isparticularly desirable when the impairing of the condition of the flooris to be avoided.

Stairs, because of their nature and the type of wear they are subjectedto, present difficulties and generally special contact adhesives areapplied to both the stairs and the covering, then after exposing theadhesive to air for a period of time to promote tackiness, the coveringis laid. However, even this method has inherent disadvantages, in thatthe solvent used for the adhesive is often inflammable, thus creating afire risk, and also while coating both the stairs and the covering, itis easy to spill or splash the adhesive onto nearby easily corrodiblearticles.

Difficulties arise in covering the riser and nose parts of the stairsatisfactorily because, in these areas, the adhesive is subjected toshear forces. The use of iron plates to hold the covering in place overthese areas while the adhesive sets fully has been tried, but is notwholly satisfactory.

The problem of providing an easy, quick and economical method of holdingstair coverings in place with adhesive has thus not been solved. Thismeans that skilled craftsmen are required, particularly for layingcarpets on intricately shaped stairs, such as winding stairs and thosewith projecting profiled edges.

SUMMARY OF THE INVENTION It is another object of the present inventionto provide an easy, quick and economical method of holding floorcovering in place by applying to the floor covering an adhesivecomposition comprising 90 to 40 parts by weight of contact adhesivecomponents which are sticky at room temperature, and which bring aboutan adhering effect, and to 60 parts by weight of synthetic thermoplasticcomponents of a conventional nature which are nonsticky at roomtemperature, but which, however, on heating to a temperature above 60 C.suffer temporary partial loss of their cohesion and become a strongsealing adhesive, which is adapted to form a permanent bond with thebase to be bonded.

Particularly on horizontal floors, the adhesive composition, at roomtemperature, is sufficient to achieve satisfactory adhesion between thecovering and the floor, merely by applying pressure thereto such asmight, for example, result from walking thereon.

The cohesion of the adhesive composition of the present invention, issuch that no adhesive remains on the floor when the covering is removed.This is unlike most, less cohesive adhesives which, on removing thecovering from the floor either separate into two layers, one remainingon the covering and the other on the floor, or more or less flow apart.

The adhesive composition has, as well as its cohesion properties,sufficient adhesion with respect to the floor covering, in that it isdeposited thereon as a fusion and consequently, the hot-tack" or the hotstickiness of the cohesive portion is utilized, in order to attain asufficient, generally permanent, bond with the base of the carpet. Thereis, of course, built into these adhesives a special sealing constituentwhich, at room temperatures, provides sufficient cohesion for adhesive,while, if subjected to higher temperatures, becomes sticky and loses itscohesive properties (called "hot-tack").

At sealing temperature, the'sealing constituent has the capacity ofexercising a strong adhesive force on most substances, even those whichare not susceptible to normal adhesives, for example plastics of thepolyolefine type, smooth metal parts or highly polished wood.

DESCRIPTION OF PREFERRED EMBODIMENTS The scaling properties of theadhesive composition are utilized, for example, in the covering of astair having built-in reinforcing nosepieces on the perpendiculars,bylaying the treated covering and then activating the sealing constituentby heating, for example with a hot-air dryer, infrared heater or simplya taper, to a temperature between 70"C.=to C., whereby the adhesivebecomes substantially softer and stickier in consistency. While theadhesive is in'this condition, the covering is pressed onto the surfaceuntil it has cooled to about room temperature. This generally continuesby the exchange of heat with the surfaces having generally a temperaturebetween 15 and 20 C. Then there occurs immediately at the places thustreated a reversible adhesion, which is surprisingly firm and consideredunusually good by expertsln this way, there is the possibility ofobtaining a permanent adhesion where the circumstances require it andthe advantages of a contact adhesive suffices.

In contrast to conventional contact adhesives, if a floor covering,coated with the adhesive composition, according to the presentinvention, is applied to a vertical wall merely by pressing, a permanentbond will not be formed and after a time the covering will fall off. Apermanent adhesion can only be attained by repeated pressure such as bywalking on a floor covering treated with the adhesive, or by theaforementioned heating and cooling process during which sealing occurs.

Thus, the adhesive of the present invention can be regarded as havingproperties intermediate between those of a contact adhesives and sealingadhesives.

A further advantage of the composition is that if it partially loses itsstickiness over a period of time at room temperature, in consequence ofsurface soiling, becoming dusty or picking up floor particles, such asgravel, concrete or wood splinters, it can easily be reactivated againby heating to a temperature between 60 C. and the melting point of theadhesive or the fibers. Rebedding of the adhesive composition takesplace causing the contaminants to resettle and become harmless.

The extent to which activation and neutralization can be carried out isof course dependent on the thickness and nature of the adhesive materialdeposited on the covering base.

It will be appreciated, that the adhesive can be used for other purposeswhere similar conditions prevail.

A typical composition, according to the present invention, of a combinedfusion, contact and sealing adhesive is given in the followingnonlimiting example.

EXAMPLE 30 part by weight 23 part by weight l5 part by weight 2 part byweight I0 part by weight I00 parts by weight.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes, andadaptions. While I have disclosed one embodiment of the presentinvention, it is to be understood that this embodiment is given byexample only and not in a limiting sense.

lclaim:

latter temperature a first degree of adhesiveness and partially losingits cohesive characteristics,

said second component being a pressure sensitive adhesion means causinga second degree of adhesiveness at room temperature, and

said second degree of adhesiveness being a cold tack releasable adhesionon a surface to which said covering material is to be secured, and saidfirst degree of adhesiveness being a nonreleasable hot tack adhesion onsaid surface.

